Rubber Blade Coating with Polyurethane Acrylate for Wear Resistance
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Solution Overview
Problem
Existing rubber squeegees with acrylate or methacrylate coatings for wear resistance suffer from poor conformability and are prone to defects like slits and cracks due to the hard and brittle nature of the cured coatings, which compromises their elasticity and cleaning effectiveness.
Innovation Solution
A method involving separate applications of a first coating composition containing isocyanate-group-terminated polyisocyanate and a second coating composition with reactive acrylate or methacrylate monomers, followed by ultraviolet light irradiation, to form a polyurethane acrylate layer that infiltrates and composites with the polyurethane elastic substrate, enhancing abrasion resistance and conformability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an acrylate or methacrylate monomer coating is applied to the working portion of the rubber substrate and cured in ultraviolet light, then wear resistance is improved, but the coating becomes hard and brittle, causing poor conformability and issues like slits and cracks
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by incorporating polyol components with specific molecular weights and hydroxyl values, along with controlled amounts of acrylate/methacrylate monomers. This parameter optimization allows the coating to achieve both wear resistance and flexibility, resolving the contradiction between hardness and conformability.
Solution Approach 2:
The patent creates a composite coating material combining polyol, polyisocyanate, and acrylate/methacrylate monomer components. This composite formulation integrates the wear resistance of acrylate/methacrylate with the flexibility of polyol-polyisocyanate systems, simultaneously achieving both improved wear resistance and maintained conformability.
2Strength
If a hard and brittle cured coating is applied to improve wear resistance, then abrasion resistance increases, but the coating is prone to defects like slits and cracks
Solution Approach 1:
The patent optimizes the molecular weight range (200-8000) and hydroxyl value (20-200 mg KOH/g) of the polyol, along with the monomer content (10-50 wt%), to create a coating that cures into a resilient structure. This parameter control prevents brittleness and defect formation while maintaining abrasion resistance, thereby improving reliability.
Solution Approach 2:
The patent incorporates flexible polyol-polyisocyanate components into the coating formulation beforehand, which act as a cushioning matrix that prevents stress concentration and crack propagation during curing and service. This preemptive structural design eliminates defects like slits and cracks before they can form under operational stress.
3Ease of operation
If the rubber substrate is deformed, then cleaning effectiveness is maintained, but the conformability of a coated surface deteriorates due to poor stretchability
Solution Approach 1:
The patent adjusts the polyol molecular weight (200-8000) and monomer content (10-50 wt%) to achieve optimal elastic recovery and stretchability in the cured coating. This parameter optimization ensures the coating can deform with the rubber substrate during cleaning operations, maintaining both conformability and cleaning effectiveness.
Solution Approach 2:
The patent develops a composite coating system where the polyol-polyisocyanate matrix provides elasticity and stretchability, while the acrylate/methacrylate components provide wear resistance. This composite structure allows the coating to flex with the substrate during deformation, maintaining surface conformability while enabling effective cleaning operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The resulting rubber blade exhibits improved abrasion resistance and conformability, reducing the likelihood of defects like slits and cracks, while maintaining the necessary flexibility for effective cleaning and durability.
Implementation Method 1
reacting the isocyanate group of the polyisocyanate with the reactive hydroxyl group of the first monomer to generate an urethane group, thereby forming a polyurethane acrylate
Implementation Method 2
solidifying the first coating composition and the second coating composition by ultraviolet light irradiating to form a hardened layer on the surface of the polyurethane elastic substrate
Data Source
AI summary
The present application discloses a method for making a rubber blade. The method includes applying a first coating composition and a second coating composition in separate steps on at least a part of a surface of a polyurethane elastic substrate; and solidifying the first coating composition and the second coating composition by ultraviolet light irradiating to form a hardened layer on the surface of the polyurethane elastic substrate. The first coating composition includes an isocyanate-group-terminated polyisocyanate and a first solvent. The second coating composition includes a first monomer, a photoinitiator, and a second solvent. The first monomer is at least one of an acrylate monomer and a methacrylate monomer each having an reactive hydroxyl group. The isocyanate group of the polyisocyanate is reacted with the reactive hydroxyl group of the first monomer to generate a urethane group to form a polyurethane acrylate. The present application also discloses a rubber blade.